Manufacture of artificial silk



tamination of the spinnerets themselves.

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MANUFACTURE OF ARTIFICIAL SILK James J. Polak, Arnhem, and Johannes G. Wealdenburg, Ede, Netherlands, assignors to American Enka Corporation, Enka, N. 0., a. corporation of Delaware No Drawing. Original application January 25,

1937, Serial No. 122,323. Divided and this application June 6, 1938, Serial No. 212,185.

Germany February 15, 1935 9 Claims.

This application is a division of our application Serial Number 122,323, filed January 25, 1937, the latter being a continuation in part of our application Serial No. 51,332, filed November 23, 1935.

The present invention has to do with a new and novel method for use in the manufacture of yarn or other materials of artificial origin and the products thereof.

More specifically, the present invention concerns a novel process for maintaining ideal spinning conditions in the manufacture of yarn of artificial origin.

In the manufacture of artificial filaments, threads, yarns, ribbons and the like, a cellulosic solution is prepared and expressed or extruded through minute openings into a coagulating or precipitating medium. This medium is usually either liquid or gaseous.

In preparing the cellulosic spinning solutions referred to in the specific examples of the present case, cellulose is treated with caustic to form alkali cellulose, which, with carbon disulphide, produces a Xauthate. This, in solution, produces a viscose spinning solution.

In the present specification we shall describe our invention with respect to a viscose process, but it must be understood that the underlying principle is broad, and that we do not wish to be limited to any specific, minute application of our concept.

In the commercial production of artificial yarn and analogous products, it is economically necessary, if possible, to provide for uninterrupted spinning ofall filaments. Ordinarily the objections arising which occasion interruptions'to the spinning or extruding step are caused by the con- This fault can, we believe, be traced to the presence of suspensions, reaction products, and impurities of various kinds in the viscose solution or the spinhing bath which tend to agglomerate or deposit on the spinneret and partially or entirely block the small orifices therein. These materials might include, among others, precipitated cellulose, sulphur deposits, particles of resin, secondary reaction products, and the like.

We have noted this phenomenon more especially when acid spinning baths are employed and particularly where zinc sulphate is present in the bath. Sulphuric acid is the acid generally used in such spinning baths.

Even if the deposit of material is insuiiicient to entirely clog the orifices, it acts to vary the thickness of the individual filaments, and consequently produces undesirable properties in the final product. Also, so-called spinning hooks tend to form at the obstructions, either in or around the orifices of the spinneret, which, when filaments are extruded therethrough, might cause a temporary interruption of the spinning of a filament at the orifice affected, thus occasioning a tearing of the filament. These faults incur additional expense due to the manipulation necessary to change spinnerets, the loss. accruing from stopped production, and the increase in lower quality yarns, for which yarns a lower price, only, may be asked.

The partial or total clogging of orifices is noticeable with the usual metal spinnerets, which spinnerets are made from gold, gold-palladium, goldplatinum, tantalum, et cetera. Furthermore, spinnerets are, manufactured from precious and semi-precious stones, such as natural ruby, synthetic rubby, et cetera. Our improved procedures are applicable in the use of these various types of spinnerets. The economic advantage of finding a simple, inexpensive method for keeping spinnerets operative during spinning is therefore apparent. As will be subsequently pointed out, other improved spinning conditions will be realized when following our procedures wherein we provide a solution for these problems in our present inventive concept.

Briefly, we have discovered that if certain cation-active compounds are included either in the spinning bath and/or the spinning solution, the clogging of spinneret openings is considerably diminished or even prevented, and a very remarkable improvement of the spinning process per se will result. More specifically, cationactive aliphatic, carbocyclic or heterocyclic substances have been employed with signal success in actual practice. By stating that certain cation-active compounds are employed it is intended to mean that only those cation-active compounds are suitable which are sufiiciently soluble and substantially stable in the spinning bath or the cellulosic solution or in both. Cationactive compounds are surface-active compounds which carry in the cation the group or radical which is responsible for the surface activity. In contradistinction anion-active Compounds are surface-active compoundswhich carryin the anion .the group which is responsible for the surface activity. Such groups responsible for surface activity in this specification are called surfaceactive groups. Other groups or ions which are inert in this respect will be called surface-inactive or innocuous.

Surface activity as used herein is the property, among other physico-chemical characteristics, of reducing surface or interfacial tension.

As-anadditional advantage we have found that when such cation-active substance are added to the viscose spinning bath, either by direct addition or as a result of addition to the viscose solution, the colloidal sulphur therein tends to agglomerate, and is easily filtered 01f if desired. Together with the removal of the sulphur thus eifected, which in itself represents an impurity, other dissolved or suspended particles contaminating the spinning bath may be also precipitated and removed.

Surface activity depends upon the presence of one or more groups or radicals with long or extended chain-like structures which include extended aliphatic, carbocyclic and heterocyclic chains or combinations thereof. Compounds which contain a surface-active group show a tendency, according to the experiments and theory of Langmuir, to accumulate in the surface or interface of the solution and to assume an oriented position in which all of the extended chalns'lie parallel. Naturally, these substances. can show this'property only insofar as they are dissolved. When the molecules ionize, the surface activity may be induced by either the cation In this structure I or the anion. This depends upon the position of the extended chain when the molecule ionizesl If, when the molecule ionizes, the extended chain remains with that part of the molecule bearing the positive charge, then it is said to be cationactive; whereas, on the other hand, if the long chain remains with that part of the molecule which bears a negative charge, it is said to be anion-active. Most of the usual surface-active substances are anion-active, with which substances the present invention is not concerned.

The compounds as exemplified below are illustrative of compounds which may be used in accordance with our invention. A-general structural formula for a compound of this type may be expressed as X Sn represents the cation and A represents the anion. X represents a polyvalent atom, or a radical containing such an atom, capable of being linked toa negative atom or radical and at the same time to one or more other atoms or radicals. The letter 3 indicates the valence of the atom or radical X, The invention also contemplates the presence of more than one atom symbolized by X in the cation. In this event one or more of the X atoms may be linked to surface-active groups and to surface-inactive atoms or radicals as described herein. S designates the radical or radicals inducing cation-activity, vwhich are linked directly to the polyvalent atom of X. S may include one or more of the same or different aliphatic, carbocyclic and heterocyclic radicals and the letter m is a positive whole number indicating the total number of such radicals. The radical or radicals S should be' such that when linked to X it or they will provide, in an ionizing solvent, a surface-active cation. B may be hydrogen and/or one. or more of the same or different aliphatic, carbocyclic or heterocyclic radical or radicals which are distinguished from those of S in that they do not induce surface-activity into the cation. The letter n is a positive whole number or zero and indicates the total number of such radicals and/or hydrogen atoms. This latter 72 also indicates the number of valences of the atom of X which remain available to be saturated by inactive atoms or radicals of the cation.

The letter A represents an innocuous anion, i. e., an anion having no surface-activity or at least less surface activity than the cation. This anion is linked directly to the polyvalent atom of X and may be an atom or an inorganic or organic radical. The letter is a whole number indicating the valence of the anion. The letter C outside of the bracket is a whole positive number indicating the numberof cations linked to the anion. In the examples given herein C equals c and the sum of n and m equals y-1.

It is to be understood that all compounds of the above named general structure have the character of bases (wherein A would be a hydroxyl radical) or their salts, including acid salts.

The more important cation-active compounds which may be employed in accordance with the present invention are the bases or their salts, such as may be derived from pentavalent nitrogen, and further the sulphonium, phosphonium and arsonium, etc. bases and their salts. The polyvalent atom of X in the foregoing formula i in these compounds nitrogen, sulphur, phosphorus and arsenic, etc., respectively. The quaternary ammonium compounds are examples of compounds containing such an atom, nitrogen being the polyvalent atom. Of these, the pyridonium or pyridinium compounds are examples of compounds in which the polyvalent atom,

nitrogen, is contained in a radical. the radical being the pyridine ring (CsHsN) having a valence of two. Other radicals containing the polyvalent atom may, oi course, be used in place of the pyridine ring.

In the bases or their salts illustrated by the above formula the innocuous anion symbolized by A is the hydroxide, chloride, sulphate, bromide, iodide, acetate, etc. The groups inducing cation activity symbolized by Sm comprise extended chain-like structures, such as aliphatic hydrocarbon chains having six or more carbon atoms therein. Also, the extended chain-like structures may be composed of two or more benzene nuclei or other cyclic radicals, either combined directly or, for example, through a carbon or nitrogen or other linkages, with or without aliphatic chains substituted for the hydrogen in rings.

Referring now in detail to specific examples of suitable compounds, bases derived from nitrogen and their salts, for instance, certain pyridinium and other quaternary ammonium compounds, have been found to be particularly suitable. The former compoundsv may include pyridinium bases or salts having linked thereto extended aliphatic chains, containing, for example, six or more carbon atoms and preferably 12 to 20 carbon atoms. Specifically, dodecyl; hexadecyl, octadecyl, or even a lower carbon chain such as decyl may be linked to the nitrogen atom in the bases or salts of pyridinium such as pyridinium hydroxide, pyridinium sulphate or bisulphate and pyridinium bromide. Use may also be made of replacement or substitute compounds such as the analogous substitution products of pyridine known as picoline (CsH4N(CH3)), and quinoline (CQHwN), etc., and also compounds such as piperidine, acridine, cinnoline and naphthyridin and their derivatives.

An example of such compound is the bisulphate or acid sulphate of dodecyl-pyridinium, having the structure:

GuHzs H804 In this compound the letter X represents the pyridine radical including the polyvalent atom nitrogen and having a valence y of 2; S is C12H25 connected directly to the polyvalent atom (nitrogen) of X, the letter m being 1. The innocuous anion A is the bisulphate radical (H804) connected directly to the polyvalent atom of X. The valence of A is l, and the letter C just out side the bracket is l. In this compound the value of n is 0, so there would harm atom or radical B.

If the other hydrogen of the bisulphate were replaced by a second dodecyl, pyridinium group the innocuous anion (S04) would have a valence of 2 and the letter C outside the bracket would become 2, indicating two dodecyl pyridinium groups satisfying the two valences of the anion.

In the bases or salts of picoline and quinoline the (C5H4N(CH3)) and the (CQHIN) groups, respectively, would be the radical X containing the polyvalent atom, nitrogen.

In the other quaternary ammonium compounds the same innocuous anions and surface-active groups may be linked to the pentavalent nitrogen atom as are employed with the pyridinium compounds. In this case X represents the atom nitrogen, having five valences. The three valences which are saturated in the pyridinium compounds by (CH) 5 are now saturated by alkyl, aryl or other carbocyclic or heterocyclic groups and/ or hydrogen atoms. For instance, three methyl groups may be usedto form trimethyl dodecyl ammonium bromide. The following is the structural formula of such a compound:

the dodecyl radical inducing the surface activity of the cation. For example, one or more of the "methyl-radicals in the above compound might be replaced by a dodecyl radical, in which event the letter m would be 2 or more, depending upon how many methyl radicals were so replaced, and the letter 11 would be correspondingly decreased. If all the methyl radicals were replaced by radicals capable of inducing the surface activity of the cation, the letter it would, of course, become zero.

As previously indicated the radicals capable of inducing the surface-activity of the cation may include aromatic or. other carbocyclic or heterocyclic radicals. The following compounds are examples of compounds containing such radicals including benzene nuclei in the surfaceactive groups in the cation: toluene azophenyl--trimethyl ammonium iodide, benzene azophenyl trimethyl ammonium iodide, diphenyl azophenyl trimethyl ammonium methyl sulphate, isopropyl naphthyl trimethyl ammonium iodide. In such compounds etc., represent the radicals inducing the surfaceactivity of. the cation (S). These may be connected to a polyvalent atom as in the ammonium salts referred to or to the polyvalent element of a radical, as in thecaseof the pyridinium and similar compounds. It is obvious that both allphatic radicals, for example, such as the dodecyl group, and carbocyclic or heterocyclic radicals, for example, such as the aromatic azo compounds referred to above, may be present in the compound as radicals inducing the surface activity of the cation. 7

Where the innocuous anion is divalent, as in the case of a sulphate in which both hydrogens are replaced by surface-active cations, a compound of the following type may be used:

di (dodecyl-triethyl ammonium) sulphate.

By the same token that the cation-active pyridonium and other ammonium compounds are suitable in connection with the present invention, sulphonium, phosphonium and arsonium bases and their salts may also be used. 'Of course, in order for this to be true, the sulphur, phosphorous or arsenic must have linked directly thereto, an innocuous anion and at least one group inducing surface activityin the cation. It is apparent that the sulphur being tetravalent, as distinguished from the pentavalent phosphorus and arsenic will have less valences to be saturated than in the case of phosphorus, arsenic and nitrogen. For example, a sulphoniurn compound such as diethyl dodecyl sulphonium hydroxide would correspond to triethyl dodecyl phosphonium hydroxide, either of which might be used. As further examples of these types of compounds, trimethyl dodecyl phosphonium hydroxide and dipropyldodecyl sulphoniurn bromide may be employed. z

It is also within the scope of our invention to use compounds in which the polyvalent atom of X is divalent or trivalent. The prerequisites of such an element must be'that they will combine surface-activity in the cation.

The following are a number of compounds that may be used in accordance with our invention:

Octyl pyridinium iodide, dodecyl pyridinlum bromide, hexadecyl pyridinium iodide, octadecyl pyridinium bromide, dodecyl pyridinium iodide, dodecyl pyridinium chloride, dodecyl-triethyl ammonium iodide, octyl-triethyl ammonium iodide, decyltriethyl ammonium iodide, dodecyltriethyl ammonium iodide, hexadecyl-triethyl ammonium iodide, toluene azophenyl-trimethyl ammonium iodide, benzene azophenyi-trimethyl ammonium iodide, diphenyl-azophenyl-t1fimethyl ammonium methys-ulphate, isopropylnaphythyltrimethyl ammonium iodide, diethyL-dodecyl sulphonium hydroxide, triethyldodecyl phosphonium hydroxide, trimethyldodecyl phosphonium iodide, trimethyl-dodecyl phosphonium bromide, dipropyl-dodecyl sulphonium bromide, etc.

Also unsaturated as well as saturated aliphatic radicals may be used as the radical inducing surface-activity in the cation (S) or as the inactive radical (R).'

' As pointed out -above, the cation-active compounds may be added directly to the viscose spinning baths, or may be mixed with the viscose solution prior to extrusion into the baths, or they may be employed simultaneously in both the bath and spinning solution. It is of course necessary to select a cation-active compound which is not adversely affected by the acid of the bath and is substantially stable when usedtherein, and/or one that is stable in viscose when used therein. Compounds which are sufiiciently soluble in dilute caustic soda or viscose to go into molecular solution in the viscose itself areparticularly adapted to beadded to the spinning solution. The tetraalkylammonium'bases'and salts and aryltrialkylammonium bases and salts are especially suited for this purpose because of their greater stability toward the alkali of the viscose. When the compound is added to the spinning bath it is preferred to use a compound that goesinto molecular solution in the spinning bath. I

We herewith give three specific examples in order to more clearly disclose the present process:

Example 1 Ordinary viscose "solution is made up; and spun or extruded through fine orifices in precious metal spinnerets into a wellknown acid spinning bath, containing sulphurioacid, sodium sulphate, am-

.monium sulphate, and a small quantity of zinc Example 2 An ordinary viscose solution is extruded through gold-palladium spinnerets into a spinning bath of the typementioned in Example 1, but which contains a relatively larger amount of zinc sulphate, for example, five per cent of this salt. Ordinarily, under these conditions, the

spinnerets become suificlently contaminated in a few hours to deleteriously aiTect spinning, as

However, if 0.1 per cent by pointed out above. weight of dodecyl trie-thyl ammonium iodide is first added to the vls'cose'so'lution, the tendency to clog the holes of thespinnerets will be greatly reduced.

An ordinary viscose solution is spun through gold-palladium spinnerets into a spinning bath containing, for example,-in addition to the usual bath ingredients 5% zinc sulphate; under these conditions the holes of the spinnerets will become contaminated withina few hours. If, however, 0.05% toluene azophenyl-trimethyl ammonium iodide is added to the viscose solution, there will be much less clogging of the spinneret holes.

We believe it remarkable that such small and relatively inexpensive amounts of substances may be employed, and still give such good results.

It must be understood that if the addition is made to the spinning bath rather than to the spinning solution, as set forth in Example 1, small further additions arenecessary from time to time to replenish the compound lost or removed during the spinning operation.

By yarn we intend to cover filaments, threads, ribbons, foils, or other products usually produced by extrusion or spinning of a so-called cellulosic solution of artificial origin.

-Having now set forth our invention as required by the Patent Statutes, we desire to be limited only to the extent set forth in the following claims.

What we claim is:

1. In the manufacture of yarn of artificial origin wherein a cellulosic solution is extruded through minute orifices into a coagulating medium to form filaments and the like therefrom, the step which comprises spinning the filaments in the presence of a dissolved cation-active compound of the class consisting of phosphonium and sulphonium bases and their salts.

2. A method as defined in claim 1 in which the compound is trimethyl-dodecyl-phosphonium iodide.

3. A method as defined in claim 1 in which the compound is dipropyl-dodecyl-sulphonium bromide.

.4. A method as defined in claim 1 in which the compound'is diethyl-dodecyl-sulphonium hydroxide.

5. In the manufacture of yarn oi" artificial origin wherein a cellulosic solution is extruded through minute orifices into a coagulating medium to form filaments and the like therefrom, the step which comprises spinning the filaments in the presence of a dissolved cation-active phosphonium salt.

6. In the manufacture of yarn of artificial origin wherein a cellulosic solution is extruded through minute orifices into a coagulating medium to form filaments and the'like therefrom, the step which comprises spinning the filaments in the presence of a dissolved cation-active sulphonium salt.

7.111 the manufacture of yarn of artificial origin wherein cellulosic solution is extruded through minute orifices into a coagulating medium to form filaments and the like therefrom, the step which comprises spinning the filaments in the presence of a dissolved cation-active sulphonium base.

8. In the manufacture of yarn of artificial meme? origin wherein a. eelluiosic solution is extruded through minute orifices into a coagulating medium to form filaments and the like therefrom, the step which comprises spinning the filaments in the presence of a dissolved cation-active phosphonium halide.

9. In the manufacture oi yarn oi. artificial origin wherein e cellulosic solution is extruded through minute orifices into a coagulating medium to form filaments and the like therefrom, the step which comprises spinning the filaments in the presence of a dissolved cation-active sulphonium halide.

JAMES J. POLAK. JOHANNES Gr. WEELDENBURG. 

